Sharp SX68JS10, Руководство по обслуживанию

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SX68JS10
8
DIGITAL COMB FILTER Y LEVEL ADJUSTMENT
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1
Digital comb filter
Y level adjust-
ment
R5406
1
Input PAL colour bar signal (100% white colour
bar) of 1.0Vp-p at the 75
Ω
terminator from AV-
IN terminal.
(Input level 1.0Vp-p
±
0.05Vp-p)
2
Connect the oscilloscope to TP5400.
3
Adjust R5406 to make the Y signal (100% white)
of TP5400 become 2.0
±
0.1Vp-p.
* Verify that all are linearly amplified. (100% white
area must not be collapsed.)
When it is adjusted at E-12ch, take
care for the voltage value.
SERVICE ADJUSTMENT
PIF CHECK ADJUSTMENT
NO. Adjustment part Adjusting procedure and conditions Waveform and others
1 RF-AGC
Cut-in adjustment
(Already preset.)
1
E-12CH (PAL Colour Bar) is received.
Electric field strength: 54
±
1dB
µ
V (75
Ω
Open)
2
Connect the oscilloscope to TP210 as shown
below.
Note: If the impedance converter of
50/75 is not used at the electric
field strength meter of 50
Ω
sys-
tem, set 52
±
1dBV for 54
±
1dB
µ
V (75
Ω
Open).
Moreover, take care for the loss
if the converter is used.
Fig. 3-1
3
Lower the input electric field strength to 51
±
1dB
µ
V (75
Ω
Open).
4
Under the conditions
1
and
3
, TP210 volt-
age does not vary.
Raise the input signal electric field strength to
60
±
1dB
µ
V (75
Ω
Open), and verify that it is
0.1V or more lower than TP210 of
1
and
3
.
5
Set the signal at 63 to 67dB
µ
V, and verify that
any noise is not output.
6
Set the signal at 90 to 95dB
µ
V, and verify that
any black letter beat is not output.
VIDEO LEVEL ADJUSTMENT
1 VIDEO DET
Level adjustment
R220
1
E-12CH B/G-PAL colour bar (100% white bar)
is received.
2
Adjust R220 to make the video output of the
AV-OUT terminal become 1.0
±
0.05Vp-p at the
75
Ω
terminator.
NO. Adjustment part Adjusting procedure and conditions Waveform and others
* If there is not any problem when the
several lots of the model which em-
ploys the relevant tuner is checked,
apply the check of only
5
and
6
.
0.1V
Bias
box
TP210
TV SET Oscilloscope
Bias Box: About 4.5V